A light deflector including a polygon mirror and a motor is known in the art. The motor typically includes a rotor that supports the polygon mirror. In one example of the light deflector, the polygon mirror has an underside that is in contact with the rotor when it is mounted to the rotor.
The polygon mirror made of plastic may be used for this purpose. In this application, heat generated in the motor may be transmitted through the rotor to the underside of the polygon mirror, and in turn transmitted from the underside to the reflecting surfaces of the polygon mirror, which would disadvantageously result in deformation of the reflecting surfaces by thermal expansion.